The present invention relates generally to tone control apparatus designed to achieve acoustic effects similar to acoustic characteristics of natural musical instruments, and more particularly to a technique for performing release control intended to achieve an acoustic effect similar to an acoustic characteristic of the acoustic (or natural) piano.
The acoustic (natural) piano is constructed to generate a performance tone in response to key depression operation by a hammer striking a string corresponding to the depressed key. Then, in response to release operation of the depressed key, a damper member corresponding to the key contacts the string to suppress vibration of the string, so that the performance tone is silenced or deadened. Each of the damper members provided in the acoustic piano is controlled in a compound manner in accordance with a plurality of operating factors, such as operational states of the corresponding key, damper pedal and sostenute pedal. Human player can control deadening (volume attenuation) of a currently generated tone by operating the corresponding key, damper pedal and sostenute pedal to control a damper position (i.e., distance between the damper member and the string).
In electronic musical instruments for electronically generating tones, on the other hand, variation over time (i.e., timewise variation) in tone volume of a tone signal to be generated is controlled in accordance with a tone volume envelope signal generated by an envelope generator. Generally, the tone volume envelope signal is controlled in accordance with parameters of an attack rate, decay rate, sustain rate and release rate.
Among various conventionally-known types of electronic keyboard instruments (hereinafter referred to as “electronic pianos”) for electronically simulating tones of the acoustic piano is one which includes, as a performance operating member, a release-controlling pedal operator, such as a damper pedal. In this type of electronic piano, it is known to detect a position of the damper pedal to control the release in accordance with the detected position of the damper pedal, and detect a position of a key during release operation of the key to control the release in accordance with the detected position of the key (see, for example, Japanese Patent Application Laid-open Publication No. HEI-10-161658.
However, in the conventionally-known electronic pianos etc., various conditions, such as a position of the damper pedal and a position of a key being released, that become factors for operating the damper member of the key, are individually handled as separate determinants of the release rate; namely, the conventionally-known electronic pianos etc. are constructed to perform release control by merely determining, for each of the conditions, a separate release rate corresponding to the operational state (i.e., position of the operating member (damper pedal, key, or the like)). Namely, with the release control in the conventionally-known electronic pianos etc., there is involved no idea of simulating a physical tone generating mechanism (release control mechanism) of the acoustic piano to determine a release rate using, as a sole parameter, a position of a damper member controlled in a compound manner in accordance with a plurality of operational factors. Because of this, a processing construction for performing the release control is fixedly connected to the hardware arrangements (like a type of the pedal employed, presence/absence of a key release position detecting mechanism, etc.) of the electronic piano, and thus, the processing construction would lack general versatility.